SOUTH LAKE TAHOE, Calif. — Community leaders have long warned of the possibility for catastrophic wildfires that would jeopardize the decades-long effort to restore Lake Tahoe's famed clarity and forest ecosystem.

As black soot settled on the lake Monday from a massive blaze raging out of control near the south shore, authorities and environmental activists took no pleasure in the fact that their predictions had come to pass.

"This is really a disaster," said Coe Swobe, a former Nevada state senator who in 1969 authored legislation creating the Tahoe Regional Planning Agency, a bistate agency charged with regulating the region's development. "The cinders and the smoke are polluting the air, which in turn pollute the waters. It will take many years to recover if this continues."

The fire began Sunday and quickly burned nearly 2,500 acres and more than 200 houses and other structures. The winds died down Monday, slowing the fire's spread, but it was just marginally contained by mid-afternoon.

All parties agreed the amount of fuel in Tahoe Basin forests had reached critical levels following years of wrangling among environmentalists and government agencies over a plan to thin forests and reduce the fire threat.

Environmental groups were wary of causing air pollution through controlled burns or jeopardizing the health of the forests by logging. Meanwhile, public officials argued among themselves over how best to address the wildfire threat without harming fragile forest ecosystems.

Plan was drafted only recentlyIn April, the U.S. Forest Service finally settled on a 10-year plan to thin and burn 38,000 acres of forest to reduce the risk of catastrophic wildfires. But it may have been too little, too late.

Ironically, the failure to thin the forests and reduce the fire threat is likely to have a far-more serious impact on the environment than controlled burns or logging, environmentalists and public officials agreed.

"The time has come to make some tough decisions to avoid more catastrophic fires," Swobe said. "I don't know what it's going to take to wake up some of these people that are against moving fast. This may be the awakening."

Extensive logging during the late 19th century clouded Tahoe's crystal blue waters, and rampant development in the popular mountain resort area during the 1960s caused soil erosion and algae growth that furthered its demise. Visibility dropped from more than 100 feet to an average of a little over 70 feet today.

A catastrophic blaze like the Angora fire can damage the watershed for years, said Rochelle Nason, executive director of the League to Save Lake Tahoe, also known as Keep Tahoe Blue.

"This is that event we've all dreaded," agreed California state Sen. Dave Cox, who represents the area.

Lt. Gov. John Garamendi, acting as governor in Gov. Arnold Schwarzenegger's absence, called the wildfire a "devastating situation, one that's going to go for some while because not just the fire, but then the recovery and the potential environmental problems that will result from this fire."

10th anniversary of Clinton summitThis year marks the 10th anniversary of a summit held by then President Clinton and Vice President Al Gore to draw attention to the restoration of Lake Tahoe, an effort that raised $1 billion from federal, state, private and local government coffers, more than half of which went to projects aimed at protecting the water quality.

About $50 million of that has been spent so far on forest thinning, brush clearing, and prescribed burns. About 462 acres burned by the Angora Fire had received some fire prevention work.

"Everyone in Lake Tahoe has been so aware of fire," said Julie Regan, spokeswoman for the Tahoe Regional Planning Agency. "We knew it wasn't a matter of 'if', but 'when' we would have a fire like this. But when you actually see it happening, you actually see the smoke rising above your own neighborhood and you have friends that are in its path, it really hits home."

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